Multiplexer

A multiplexer comprising:

• a first filter including one or more series resonators connected in series between a common terminal and a first terminal and one or more parallel resonators connected in parallel between the common terminal and the first terminal, each of the one or more series resonators and the one or more parallel resonators including an IDT located on a piezoelectric substrate, a first region and a second region being alternately located in an extension direction of electrode fingers, which excite an acoustic wave, within an overlap region of the IDT, a thickness of an additional film located on at least one of the electrode fingers in the second region being greater than the thickness of the additional film located on the at least one of the electrode fingers in the first region, the electrode fingers overlapping in the overlap region, one or some resonators of the one or more parallel resonators and the one or more series resonators having a larger number of the second regions than one or more remaining resonators of the one or more parallel resonators and the one or more series resonators;
• and
• a second filter connected between the common terminal and a second terminal, the second filter having a passband higher than a passband of the first filter,
• wherein an emphasis mode of each of the one or some resonators is located at a frequency higher than the passband of the second filter.

A multiplexer comprising:

• a first filter including one or more series resonators connected in series between a common terminal and a first terminal and one or more parallel resonators connected in parallel between the common terminal and the first terminal, each of the one or more series resonators and the one or more parallel resonators including an IDT located on a piezoelectric substrate, a first region and a second region being alternately located in an extension direction of electrode fingers, which excite an acoustic wave, within an overlap region of the IDT, an acoustic velocity in the second region being less than the acoustic velocity in the first region, the electrode fingers overlapping in the overlap region, one or some resonators of the one or more parallel resonators and the one or more series resonators having a larger number of the second regions than one or more remaining resonators of the one or more parallel resonators and the one or more series resonators;
• and
• a second filter connected between the common terminal and a second terminal, the second filter having a passband higher than a passband of the first filter,
• wherein an emphasis mode of each of the one or some resonators is located at a frequency higher than the passband of the second filter.